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<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>
<body>
<script type="text/javascript" >
  var s='test=function (){return 1;}'; //一个函数定义语句
  function demo2(){
    eval(s);
     alert(test())
    eval('aa=123');
   }
demo2();
alert(aa);
alert(test()); //->error:test is not defined

var s='global'; //定义一个全局变量
function demo1(){
//eval('var s="local"');
eval('s="local"');
}
//demo1();
alert(s); //->global

</script>
</body>
</html>
